From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27F7EC04EB8 for ; Mon, 10 Dec 2018 11:23:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E38D52084E for ; Mon, 10 Dec 2018 11:23:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E38D52084E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727057AbeLJLXd (ORCPT ); Mon, 10 Dec 2018 06:23:33 -0500 Received: from mail.us.es ([193.147.175.20]:50350 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726847AbeLJLXd (ORCPT ); Mon, 10 Dec 2018 06:23:33 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id A5504443824 for ; Mon, 10 Dec 2018 12:23:30 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 5925ADA4D1 for ; Mon, 10 Dec 2018 12:23:30 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 3BF61DA80D; Mon, 10 Dec 2018 12:23:30 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 75866DA4F6; Mon, 10 Dec 2018 12:23:23 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Mon, 10 Dec 2018 12:23:23 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (sys.soleta.eu [212.170.55.40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id 441EF4265A4C; Mon, 10 Dec 2018 12:23:23 +0100 (CET) Date: Mon, 10 Dec 2018 12:23:22 +0100 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Linus =?iso-8859-1?Q?L=FCssing?= Cc: netfilter-devel@vger.kernel.org, Jozsef Kadlecsik , Florian Westphal , Roopa Prabhu , Nikolay Aleksandrov , "David S . Miller" , coreteam@netfilter.org, bridge@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v2] netfilter: ebtables: avoid resetting limit rule state Message-ID: <20181210112322.rxndlqmfckctbhjm@salvia> References: <20181209061405.15112-1-linus.luessing@c0d3.blue> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20181209061405.15112-1-linus.luessing@c0d3.blue> User-Agent: NeoMutt/20170113 (1.7.2) X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Linus, On Sun, Dec 09, 2018 at 07:14:05AM +0100, Linus Lüssing wrote: > So far any changes with ebtables will reset the state of limit rules, > leading to spikes in traffic. This is especially noticeable if changes > are done frequently, for instance via a daemon. > > This patch fixes this by bailing out from (re)setting if the limit > rule was initialized before. > > When sending packets every 250ms for 600s, with a > "--limit 1/sec --limit-burst 50" rule and a command like this > in the background: > > $ ebtables -N VOIDCHAIN > $ while true; do ebtables -F VOIDCHAIN; sleep 30; done > > The results are: > > Before: ~1600 packets > After: 650 packets > > This also aligns the behavior to "xtables-nft-multi ebtables" which uses > nft_limit instead of ebt_limit. In tests nft_limit did not suffer from > this issue and rate limited to 650 just fine. > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Linus Lüssing > > --- > > Changelog v2: > > - Adjusted commit message (adjusted title, added test results with > nft_limit for comparison) > - Excluded rate limiting variables from zeroing when passed to userspace > by increasing .usersize. This became necessary with 4.11 / > commit ec2318904965 ("xtables: extend matches and targets with .usersize") > - Retested with 4.20-rc4 and current net-next/master (83af01ba1c2d) > > v1 was: > > "[net-next] bridge: ebtables: Avoid resetting limit rule state" > -> https://lore.kernel.org/patchwork/patch/854802/ > --- > net/bridge/netfilter/ebt_limit.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/net/bridge/netfilter/ebt_limit.c b/net/bridge/netfilter/ebt_limit.c > index 165b9d678cf1..2cf9861c3bce 100644 > --- a/net/bridge/netfilter/ebt_limit.c > +++ b/net/bridge/netfilter/ebt_limit.c > @@ -69,6 +69,10 @@ static int ebt_limit_mt_check(const struct xt_mtchk_param *par) > { > struct ebt_limit_info *info = par->matchinfo; > > + /* Do not reset state on unrelated table changes */ > + if (info->prev) > + return 0; Hm, still I don't think we can follow this path, even if it works. This means we trust userspace in what it sets for info->prev. Using ebtables-nft (instead of ebtables-legacy) fixes this problem, without this patch. > + > /* Check for overflow. */ > if (info->burst == 0 || > user2credits(info->avg * info->burst) < user2credits(info->avg)) { > @@ -105,7 +109,7 @@ static struct xt_match ebt_limit_mt_reg __read_mostly = { > .match = ebt_limit_mt, > .checkentry = ebt_limit_mt_check, > .matchsize = sizeof(struct ebt_limit_info), > - .usersize = offsetof(struct ebt_limit_info, prev), > + .usersize = sizeof(struct ebt_limit_info), > #ifdef CONFIG_COMPAT > .compatsize = sizeof(struct ebt_compat_limit_info), > #endif > -- > 2.11.0 >